Transfer tracks are used to transfer packaged integrated circuits to equipment such as integrated circuit testing equipment, integrated circuit inspection equipment, and circuit board assembly equipment.
A typical transfer track is illustrated in FIG. 1A.
The transfer track consists of a transfer track rail 100 with a track slot 102 in which packaged integrated circuits 122 such as QFN (Quad-Flat No leads) packaged integrated circuits, are placed end-to-end in a row.
A transfer track head 104 with a packaged IC slot 105 of sufficient size to receive one packaged IC 122 alternatively engages and disengages with the transfer track rail 100 during the packaged IC 122 transfer operation. A tab 106 on the transfer track head 104 mates with an opening 107 in the lead end of the transfer track rail 100 to ensure proper alignment of the packaged IC slot 105 with the transfer track slot 102 during engagement.
A stopper arm 118 with a cam 114 is attached to the transfer track rail 100 with a pivot 116. A stopper 108 attached to the upper end of the stopper arm 118 presses down on the lead packaged IC 122 at the lead end of the transfer track rail 100 to prevent it from moving when the transfer track head 104 disengages and reengages with the transfer track rail 100.
A transfer head arm 110 with a cam follower 112 is attached to the transfer head 104. As the transfer head 104 engages and disengages with the transfer track rail 100 the cam follower 112 actuates the cam 114 causing the stopper arm 118 to to clamp and unclamp the lead packaged IC 122.
The major steps in the operation of the transfer track are illustrated in FIGS. 1A through 1F.
As shown in FIG. 1A, the lead packaged IC 122 is clamped in place by the stopper 108 attached to the upper end of the stopper arm 118 when the transfer head 104 is disengaged from the transfer rail 100.
In FIG. 1B, the transfer track head 104 mates with the transfer track 100. As the transfer head 104 mates with the transfer track 100, the cam follower 112 on the transfer head arm 110 actuates the cam 114 on the stopper arm 118 causing the stopper arm 118 to pivot. The pivoting motion causes the stopper 108 to lift up and to unclamp the lead packaged IC 122.
As is illustrated in FIG. 1C the packaged ICs 112 are then advanced along the transfer track slot 102 causing the lead packaged ICs 112 to be transferred from the transfer track slot 102 on the transfer track 100 to the packaged IC slot 105 on the transfer head 104.
In FIG. 1D, the transfer head 104 now containing the lead packaged IC 122 in the packaged IC slot 105 disengages from the transfer rail 100. As the transfer head 104 disengages from the transfer rail 100, the cam follower 112 on the transfer head arm 110 separates from the cam 114 on the stopper arm 118 causing the stopper arm 118 to pivot so that the stopper 108 clamps down on the packaged IC 122 that now occupies the lead position in the transfer track slot 102.
A pick-up tip 120 then picks up the packaged IC 122 from the transfer head 104 as illustrated in FIGS. 1E and 1F.
After the packaged IC 122 is transferred to the equipment, the transfer track 100 is ready to repeat the process and to transfer the next packaged IC 122 to the equipment.